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Endogenous opioids support the spinal inhibitory action of an α2-adrenoceptor agonist in the decerebrated, spinalised rabbit
- Source :
-
Neuroscience Letters . Apr2003, Vol. 340 Issue 2, p95. 4p. - Publication Year :
- 2003
-
Abstract
- The present study examined the possible contribution of endogenous opioids to inhibition of spinal reflexes by an α2-adrenoceptor agonist. In rabbits decerebrated and spinalised under halothane/nitrous oxide anaesthesia, the selective α2-adrenoceptor agonist dexmedetomidine (3–30 μg intrathecal) induced significant decreases in short- and long-latency reflex responses evoked in medial gastrocnemius (MG) motoneurones by stimulation of the sural nerve. After recovery from dexmedetomidine, the μ-opioid receptor antagonist β-funaltrexamine (β-FNA; 100 μg intrathecal) significantly enhanced short-latency but not long-latency MG reflex responses. After β-FNA, inhibition of all reflexes by dexmedetomidine was significantly weaker than in the control state, whereas the cardiovascular actions of dexmedetomidine were unaffected. These data confirm that activation of spinal α2-adrenoceptors depresses MG reflexes evoked by all groups of sural nerve afferent fibres, and shows that endogenous opioid tone supports the inhibitory action of α2 agonists, possibly by a synergistic interaction in the spinal cord. [Copyright &y& Elsevier]
- Subjects :
- *SPINAL cord
*NOCICEPTORS
Subjects
Details
- Language :
- English
- ISSN :
- 03043940
- Volume :
- 340
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Neuroscience Letters
- Publication Type :
- Academic Journal
- Accession number :
- 9404064
- Full Text :
- https://doi.org/10.1016/S0304-3940(03)00021-1